Buggy code:
r [ 0 ] = new POP3CommandReference ( controller . getServer ( ) ) ; FetchNewMessagesCommand c = new FetchNewMessagesCommand ( frameController , r ) ; processor . addOp ( c ) ; } } else if ( action . equals ( "RECEIVE" ) ) { System . out . println ( "receive<seq2seq4repair_space>messages" ) ; POP3ServerController [ ] list = popServerCollection . getList ( ) ; for ( int i = 0 ; i < ( list . length ) ; i ++ ) { POP3ServerController controller = ( ( POP3ServerController ) ( list [ i ] ) ) ; POP3CommandReference [ ] r = new POP3CommandReference [ 1 ] ; r [ 0 ] = new POP3CommandReference ( controller . getServer ( ) ) ; FetchNewMessagesCommand c = new FetchNewMessagesCommand ( frameController , r ) ; processor . addOp ( c ) ; } } else if ( action . equals ( "SEND" ) ) { System . out . println ( "send<seq2seq4repair_space>messages" ) ; FolderCommandReference [ ] r = new FolderCommandReference [ 1 ] ; OutboxFolder folder = ( ( OutboxFolder ) ( treeModel . getFolder ( 103 ) ) ) ; r [ 0 ] = new FolderCommandReference ( folder ) ; SendAllMessagesCommand c = new SendAllMessagesCommand ( frameController , r ) ; processor . addOp ( c ) ; } else if ( action . equals ( "VIEW_TOOLBAR" ) ) { System . out . println ( "show<seq2seq4repair_space>toolbar" ) ; boolean folderInfo = MailConfig . getMainFrameOptionsConfig ( ) . getWindowItem ( ) . isShowFolderInfo ( ) ; if ( ( MailConfig . getMainFrameOptionsConfig ( ) . getWindowItem ( ) . isShowToolbar ( ) ) == true ) { frameController . getView ( ) . hideToolbar ( folderInfo ) ; MailConfig . getMainFrameOptionsConfig ( ) . getWindowItem ( ) . setShowToolbar ( "false" ) ; } else { frameController . getView ( ) . showToolbar ( folderInfo ) ; MailConfig . getMainFrameOptionsConfig ( ) . getWindowItem ( ) . setShowToolbar ( "true" ) ; } } else if ( action . equals ( "VIEW_FILTERTOOLBAR" ) ) { System . out . println ( "show<seq2seq4repair_space>filtertoolbar" ) ; if ( ( MailConfig . getMainFrameOptionsConfig ( ) . getWindowItem ( ) . isShowFilterToolbar ( ) ) == true ) { frameController . getView ( ) . hideFilterToolbar ( ) ; MailConfig . getMainFrameOptionsConfig ( ) . getWindowItem ( ) . setShowFilterToolbar ( "false" ) ; } else { frameController . getView ( ) . showFilterToolbar ( ) ; MailConfig . getMainFrameOptionsConfig ( ) . getWindowItem ( ) . setShowFilterToolbar ( "true" ) ; } } else if ( action . equals ( "VIEW_FOLDERINFO" ) ) { System . out . println ( "show<seq2seq4repair_space>folderinfo" ) ; boolean toolbar = MailConfig . getMainFrameOptionsConfig ( ) . getWindowItem ( ) . isShowToolbar ( ) ; if ( ( MailConfig . getMainFrameOptionsConfig ( ) . getWindowItem ( ) . isShowFolderInfo ( ) ) == true ) { frameController . getView ( ) . hideFolderInfo ( toolbar ) ; MailConfig . getMainFrameOptionsConfig ( ) . getWindowItem ( ) . setShowFolderInfo ( "false" ) ; } else { frameController . getView ( ) . showFolderInfo ( toolbar ) ; MailConfig . getMainFrameOptionsConfig ( ) . getWindowItem ( ) . setShowFolderInfo ( "true" ) ; } } else if ( action . equals ( "USE_ADVANCEDVIEWER" ) ) { } else if ( action . equals ( "ABOUT" ) ) { AboutDialog dialog = new AboutDialog ( ) ; } else if ( action . equals ( "ADDRESSBOOK" ) ) { frame . setVisible ( true ) ; } else if ( action . equals ( "MAIN_PREFERENCES" ) ) { } else if ( action . equals ( "IMPORT" ) ) { ImportWizard wizard = new ImportWizard ( ) ; } else if ( action . equals ( "GENERAL_OPTIONS" ) ) { GeneralOptionsDialog dialog = new GeneralOptionsDialog ( frameController . getView ( ) ) ; dialog . updateComponents ( true ) ; dialog . setVisible ( true ) ; if ( ( dialog . getResult ( ) ) == true ) { dialog . updateComponents ( false ) ; ThemeSwitcher . setTheme ( ) ; ThemeSwitcher . updateFrame ( frameController . getView ( ) ) ; } } else if ( action . equals ( "HOMEPAGE" ) ) { URLController c = new URLController ( ) ; try { c . open ( new URL ( "http:////columba.sourceforge.net" ) ) ; } catch ( MalformedURLException mue ) { } } else if ( action . equals ( "FAQ" ) ) { URLController c = new URLController ( ) ; try { c . open ( new URL ( "http:////columba.sourceforge.net//index.php?page=faq" ) ) ; } catch ( MalformedURLException mue ) { } } else if ( action . equals ( "LICENSE" ) ) { URLController c = new URLController ( ) ; try { c . open ( new URL ( "http:////columba.sourceforge.net//index.php?page=license" ) ) ; } catch ( MalformedURLException mue ) { } } else if ( action . equals ( "BUGREPORT" ) ) { URLController c = new URLController ( ) ; try { c . open ( new URL ( "http:////www.sourceforge.net//projects//columba//bugs" ) ) ; } catch ( MalformedURLException mue ) { } } else if ( action . equals ( "SOURCEFORGE" ) ) { URLController c = new URLController ( ) ; try { c . open ( new URL ( "http:////www.sourceforge.net//projects//columba" ) ) ; } catch ( MalformedURLException mue ) { } } else if ( action . equals ( "EXIT" ) ) { <START_BUG> frameController . closeColumba ( ) ; <END_BUG> } else if ( action . equals ( "NEW_MESSAGE" ) ) { ComposerController controller = new ComposerController ( frameController ) ; controller . showComposerWindow ( ) ; } else if ( action . equals ( "OPEN_NEW_WINDOW" ) ) { MailFrameController c = new MailFrameController ( ) ; c . getView ( ) . show ( ) ; } } }

Fix:
frameController . close ( ) ;